Boat and boat construction



p 2} 19.47. HQM L. DAVIDSON 2,426,729

BOAT AND BOA'T CONSTRUCTION Filed Jan. 2, 1945 2 Sheets-Sheet'l l/wmroe fimsu 41 1509 DAV/D301! ggwxzz" Sept. 2, 1947. MOL. DAVIDSON 9 BOAT AND BOAT CONSTRUCTION Filed Jan. 2, 1945 2 Sheets-Sheet ,2

. llWf/YTOE llmlsw M 1500 DAY/050A TTOR/VEY Patented Sept. 2, 1947 BOAT AND BOAT CONSTRUCTION Hamish McLeod Davidson, West Vancouver,

British Columbia, Canada Application January 2, 1945, serial No. 571,042

My invention relates to improvements in boats and boat construction, which are particularly adapted for use as rowboats, launches, canoes and other'water craft.

The objects of the invention are to provide a method of producing laminated boats and the like in which the length of veneer extends in varying directions both lengthwise and crosswise of the vessel; to provide a boat having the finished appearance of the conventional carvel built or smooth skin boat with its strakes running from stem to stem, and also to provide means whereby different woods may be used to cover the undersideof the boat if desired to take care of wear when grounding'on a beach. A further object is to provide a structure which will maintain its shape and be free from any tendency to straighten out in case of major damage to any part of its wall area. A still further object is to provide a structure which is of such rigidity as to preclude the need of ribs, thus leaving the hull free from such crevices which in normally built boats are usually the source of decay unless perfectly cleaned out from time to time.

The invention consists of a boat made up of laminations running lengthwise of the hull and intermediate plies of laminations running from side to side, all of which are laid upon a mold and are compressed into intimate contact with each other uponsaid mold during the bonding of the superposed laminations.

Referring to the drawings:

Fig. 1 is a perspective view of the mold upon which the boat hull is formed.

Fig. 2 is a perspective view of the mold showing sections of the several plies of material set in place.

Fig. 3 is a perspective view showing the manner of compressing the several plies during the adhesive setting.

Fig. 4 is a rear end View of the boat.

Figs. 5 and 6 are detail views of the stem post.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral l indicates a bench upon which is placed a mold 2 conforming in its upper portion as at 3 to the shape of the boat to be built, the lower portion 4 of said mold has sides vertically in alignment with the lower edge of the upper portion 3, so as to provide a temporary fastening to the boat material. A portion 5 is cut away at the prow of the mold to receive a stem post 1, see Figures 5, 6 and 4 and provision is made as at 8 at the stern of the mold to accommodate a transom l0,'see Figure 4.

The stem post 1 and the transom In are held in place upon the mold 2 by any appropriate temporary means and the first ply of veneer as shown in the section A' of Figure 2 is applied. The first ply consists of longitudinally disposed strips I2 5 Claims. (01. 96)" 2 all of which are cut to shape to conform to the normal shape of the strakes used in carvel boat building. These strips I2 are preferably around I three thirty-seconds of an inch in thickness and may be slightly thicker since they are not subject to any sharp bending. The stem post I is provided with a substantially flat area l4, as shown at E of Figures 5 and 6, and is bevelled progressively on opposite sides as at F and G, so that each garboard strake may merge on meeting the stem post from a substantially flat position to an incline. The stem post and transom are appropriately coated with adhesive before the first ply is applied to the mold. The strips l2 are fitted in place upon the mold with their adjacent side edges substantially abutting each other and are secured to the mold if deemed desirable and also secured to the edge of the transom and the bevels F and G of the stem post.

The first ply having been completed, it is coated liberally with an adhesive, preferably of the cold setting synthetic resin type, to substantially fill the material and any slight spaces between adjacent strips. A second ply, consisting of parallel sided strips of material 16 which is preferably of a thinner material than the inner and outer plies, say one thirty-second of an inch, is applied.' The strips l6 are laid diagonally from gunwale to gunwale as shown in the section B of Figure 2. It will be obvious that towards the top sides of the boat the strips 16 will overlap, should said overlap be excessive they may be trimmed off with scissors or other convenient tool so that all parts of the several plies will lie relatively close to the mold surface.

When the second ply is put in place, the free ends of the strips it are secured to the lower portion 4 of the mold as indicated at ll, the entire mold is placed into an airtight bag l8, see Figure 3, the end of which is folded and rendered airtight by clamps l9 or other suitable means, and the'air is exhausted say to a gauge pressure of twenty-six or more inches, which causes the material of the bag to bear down over the entire area of the boat and compress its plies l2 and [6 into "substantially smooth and intimate contact with each other. The boat is allowed to stand in the bag until the adhesive is substantially set and the material of the strips has taken its appointed curvature.

Th boat and its mold are then removed from the bag I8 and rough spots in the strips 16 are removed by light planing or otherwise and a further heavy coat of adhesive is applied all over the ply surface, substantially impregnating it. A third ply of thin strips 22 is applied over the wet adhesive and is laid diagonally at substantially degrees from the direction of the strips it, see section C of Figure 2. The free ends of the strips 22 are secured to the lower portion 4 of 2. The method of building a boat hull which comprises the covering of a mold shaped to conform to the shape of the hullwith inner, intermediate and'outer plies of strip material in'the following steps, first covering said mold with an inner ply extending longitudinally, of the hull,

the underwater portion of the boat may be thick- I er than those of the freeboard and may also be of hardwood to increase the wearing qualities. On completion of the outer ply, the boat and its mold are again put into the bag and theair exhausted therefrom to compress the several plies together and onto the mold surface, the structure remaining in said bag until the adhesive is properly set. v r

It more than three laminations of material are used, it will be preferable to enclose the structure in'ithe bagand exhaustth'e air therefrom'after each two or three plies are applied.v By this means the plies are pressed into intimate contact with each other more readily and 'the ultimate setting and hardening of the adhesive and ply material is accomplished in less time.

On removal of the boat and mold from the bag,

I rough'spots are trimmed or sanded down, the

projecting edges of the several strips'are trimmed off and the boat is removed from the mold ready to fit the gunwale bead, the thwarts and any. other trim r fitting required. 7 r

If the boat is of such dimensions that the use of ribs or other members are-desirable, such ribs may be housed'in suitable grooves formed inv the mold 2 as indicated in dotted line as at R in Fig-' ure 1 and the inner strips secured to them by adhesive and tacking during construction of the molded hull and secured bynails or rivets in the usual way after the hull is' removed from the mold;

The transom may be put in position after the laminated portion of the boat is completed.

It will be obvious that while wood veneers alone are referred to, other sheet material in strip form maybe used either in whole or in combination with the'wo'od.

By using vacuum to press the laminations to the mold there is no need for expensive press equipment and pressure can be applied over a circumferential distance of over 180 degrees without resort to duplicating equipment such as would be necessary if the boat was pressed in the inte'rior of a mold. a j What'I claim as my inventionisz 1. Themethod 'of building a boat hull which comprises fitting a stempost to a mold shaped to conform to the shape of theboat, securing shaped strips of material to the stem post-and: extending them lengthwise of the mold to form an'inner ply, applying an adhesive to said inner ply, laying one or more intermediate plies of strips diagonally over the inner ply andsecuring Said'strips to themold; applying adhesive to each successive ply, enclosing the mold and its cover:

plies with a flexible airtight covering, exhausting the air from the covering to compressthecover plies to the mold during the setting of the-,ad-

ing longitudinally of the mold and being secured to the 'stempost, andpressing the several plies into intimate contact with; each other during the setting of the adhesive by air pressure means.

the strips of said ply being shaped to lie in close side by side relation, applying adhesive and an and enclosing the mold and its cover plies in an claimed;- in claim 2, wherein the intermediate ply airtight flexible covering, exhausting the air from said covering to intimately press said intermediate, ply to the inner ply during the setting of the adhesive, next removing the mold and'its plies fromthe covering. and applying further adhesive 7 and an outer ply to the set intermediate plies and again enclosing the. mold andits coverpli'es with in the covering and-exhausting the airtocoinpress said outer plies during the setting of the adhesive. 1

3. The method of building1aboathul1 as consists of substantially parallel sidedthin strips of material and some of its side edges overlap other side edges ofad'jacent strips.

4. The method of building a :boat hull as claimed in claim' 2, wherein the intermediate ply consists of substantially parallel sided thinstrips of material and some of its sideedges overlap other side edges ofadjacent strips 'and'undes'irable overlapping portions are trimmedoif prior to the application of a subsequent plyfof; strip material. f e I 5. The method of-building a boat hull which comprises the covering of a mold shaped to conform to the shape ofthe hull with inner, intermediateland outer plies of strip material in the following steps, first covering said mold withian inner ply, the strips of "said ply being shaped to lie in close sideby side relation, applying ad'- hesive and an intermediateply to'said inner ply,,

said intermediate ply being laid diagonally to the inner ply, securingls'aid intermediate ply to the mold and enclosingftheYmold' and its cover pliesin an airtight flexible covering, exhausting the air from said covering tofintimatelypre'ss.

said intermediate ply to the inner ply during the setting of the adhesive, next removing the'mold I and its plies from the covering and applying further adhesive and an outer vply to theset intermediate piles and again enclosing the Imold and its cover plies within the covering andex-o hausting the air to compress said outer plies dur-' ing the setting oil the adhesive. e 1

HAMIIVVSHH Mcrnop DAv'IDsoril w REFERENCES chm 7' T mjoivi-ngjreferences are ofjrecord in, the file of this "patentz j I 7 I emetic, s'rATEs PATENTS 

